I also take along a multimeter, wire, connectors and crimper.
Additionally, my "go kit" for an old car includes:

Typical screwdriver/wrench/socket tool assortment including cable ties, tape, wire, emery cloth, scissors, wire cutters, point file and feeler gauge. Sometimes I've even brought along a sheet of gasket material;
A gallon of water for an unexpected coolant leak - the jug could also be used to schlep gasoline should you develop a fuel leak;
Spare fan belt;
Spare fuel pump;
Generic coil;
Quart or two of oil;
Spare key;
That's about all I take as extras.

You may want to crack/re-tighten your lug nuts before the trip.

Long trips in old cars are awesome. It's like taking a step back in time and there is such a feeling of accomplishment when you make it to your destination and back without a breakdown.